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Gram stain Culture

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Colony of Actinomyces within an abscess. A Gram stain is needed to see the filamentous organisms. Large colonies of Actinomyces can appear macroscopically as yellow granules whch have been termed "sulfur granules". The darkly staining eosinophilic rim at the periphery of the colonly consists of immunoglobulin and cell debris which is referred to as the Splendore-Hoeppli phenomenon. This deposition occurs around colonies of fungi and bacteria and around parasitic organisms

Author: Yale Rosen / Wikimedia Commons

https://commons.wikimedia.org/wiki/File:Actinomycosis_2.jpg

Actinomyces israelii

General information

the following information is not yet verifiedTaxonomy Family: Actinomycetaceae

Natural habitats This bacteria is a natural component of the human gastrointestinal and oral flora

Clinical significance Altough they are not normally a disease causing organism, it is the primary causative agent of Actinomycosis, a long term infection that commonly affects the face and neck.

They form the characteristic aggregates of branching bacilli seen macroscopically as "sulpher granules", there are always multiple species present.

Actinomycosis The disease is characterised by the formation of painful abscesses in the mouth, lungs or gastrointestinale tract.

Actinomycosis abscesses grow larger as the disease progresses, often over months.

Gram stain

the following information is not yet verified
Gram positive branching rods

Culture characteristics

the following information is not yet verified

Anaerobic to microaerophilic

They grow better anaerobic than aerobic, or grow poorly or not at all aerobic, but after a number of subcultures they grow aerobically / CO2

Blood Agar The colonies have a rough (“molar tooth”) or smooth surface, not hemolytic

Brucella Blood Agar Ø

- rough colonies: young (2-3 days old) growing like spider shaped colonies they grow a typical shape of a “molar tooth” or “breadcrumb”, often sandy (gritty), hard and stick to the agar (7-14 days), non-hemolytic

- smooth colonies: are slightly elevated, white crème, and opaque

Approximately one third of the strains are smooth and grow faster. In 2-3 days they are 1-2 mm.